The Japan Championship Series(日本選手権シリーズ,Nippon Senshuken Shiriizu?), or Japan Series(日本シリーズ,Nippon Shiriizu?) is the annual championship series in Nippon Professional Baseball and the top baseball league in Japan. It is a seven-game series between the winning clubs of the league's two circuits, the Central League and the Pacific League. The Series is the highest level of play in professional baseball in Japan. It is usually played in October or November. As in all of the best-of-seven series, the first team to win four games is the overall winner and is declared the Japan Series Champion (日本一,Nippon Ichi?, number one in Japan) each year. The winner of the Japan Series also goes on to be the Japanese representative team in the annual Asia Series.
The home team for games 1, 2 and eventually 6 and 7, alternates between the two leagues with the Pacific League having the advantage on the years ending with an odd number and the Central League on the years ending with an even number. Designated hitters are used if the team from the Pacific League hosts the game. There is a 40-man postseason roster limit, and the rule on drawn games is changed to 15 innings instead of 12. If the series is tied after the seventh game, a Game 8 will be held without any limits in extra innings with the same team hosting Games 6 and 7 hosting this game. Only once a Game 8 has been played in Japan Series history, where the Seibu Lions defeated the Hiroshima Toyo Carp in 1986.
Historically, the Central League has been more successful in the Japan Series than the Pacific League, having won thirty-five times versus the Pacific League's thirty. The team with the most championships is the Yomiuri Giants, who have won the Japan Series twenty-two times. In 2004, the Pacific League instituted a three-team stepladder playoff format to determine the league champion, while the Central League champion had a long wait before the Japan Series. During this time, the Pacific League won four consecutive Series from 2003-2006. Starting with the 2007 postseason, both leagues adopted the Climax Series to determine their champions. The Climax Series involves the top three finishers in each league, though the format gives a significant advantage to the team with the best record in each league.
1The franchise currently known as the Saitama Seibu Lions had a Japan Series record of 3–2 as the Nishitetsu Lions. 2The franchise currently known as the Fukuoka SoftBank Hawks had a Japan Series record of 2–8 as the Nankai Hawks. 3The franchise currently known as the Orix Buffaloes had a Japan Series record of 3–7 as the Hankyu Braves, and 1–1 as the Orix BlueWave. It took its current name in 2005 after merging with the Osaka Kintetsu Buffaloes. 4The franchise currently known as the Chiba Lotte Marines had a Japan Series record of 1–0 as the Mainichi Orions, 0–1 as the Daimai Orions, and 1–1 as the Lotte Orions. 5The franchise currently known as the Hokkaido Nippon-Ham Fighters had a Japan Series record of 1–0 as the Toei Flyers. 6The franchise currently known as the Yokohama BayStars had a Japan Series record of 1–0 as the Taiyō Whales. 7The Osaka Kintetsu Buffaloes were merged with the Orix BlueWave in 2005 to form the Orix Buffaloes. 8The Shochiku Robins were merged with the Taiyō Whales in 1953, eventually becoming the Yokohama BayStars.
The Yomiuri Giants won 9 consecutive Japan Series championships from 1965 to 1973. The second-longest streak is 3 consecutive championships, accomplished by the Yomiuri Giants (1951–1953), the Nishitetsu Lions (1956–1958), the Hankyu Braves (1975–1977), and twice by the Seibu Lions (1986–1988 and 1990–1992).
The Yomiuri Giants also won 5 consecutive Central League pennants from 1955 to 1959, and 19 of the 23 Central League pennants from 1951 to 1973. The Giants also won two consecutive Central League pennants on several other occasions. The only other teams to win consecutive Central League pennants are the Hiroshima Toyo Carp (1979–1980), the Yakult Swallows (1992–1993), and the Chunichi Dragons twice (2006–2007 and 2010–2011).
The Nankai Hawks won 3 consecutive Pacific League pennants twice (1951–1953 and 1964–1966). The Hankyu Braves won 9 of the 12 Pacific League pennants from 1967 to 1978, including 3 consecutive (1967–1969) and 4 consecutive (1975–1978). The Seibu Lions won 11 of the 14 Pacific League pennants from 1985 to 1998, including 4 consecutive (1985–1988) and 5 consecutive (1990–1994).
Franchises have gone 20 years or more without a Japan Series championship over the following intervals: